swift - Appending tuples to an array of tuples

Question

My class declares an array

var laps: (start: NSDate!, end: NSDate!)[] = []

When a tuple is added to this array I'd like to be able to do something like

let now = NSDate()
var lap = (now, nil)
laps.append(lap)

But at the append I get the error Missing argument for parameter 'end' in call.

Answer 1

I've tried to following, and it looked correct syntactically:

typealias MyTuple = (start: NSDate!, end: NSDate?)

then in the method, I did:

var laps: Array<MyTuple> = Array()
laps.append((NSDate.date(), nil))